In the medical field, hitherto, there has widely been used a method whereby aggregation patterns of blood particles, latex particles, carbon particles, and the like are discriminated and various components (for instance, blood type and various antibodies, or various proteins, etc.) in the blood, viruses, and the like are detected and analyzed. As a method of discriminating the aggregation patterns, a microtiter method is frequently used.
According to the microtiter method in immunology measurement, the blood is aggregated on a microplate by a predetermined method, and the presence or absence of the aggregation is examined or an area or the like of the aggregation pattern is calculated, thereby executing a fine measurement of an immune component. Hitherto, the presence or absence of the aggregation has been discriminated by visual observation. However, in recent years, automatization of such a discrimination has also progressed.
In the discrimination of the aggregation pattern, the presence or absence of an aggregation is synthetically judged in a manner such that a distribution of the particles in a well (i.e. reactive vessel) is detected as an area of the portions whose luminance are equal to or less than a predetermined luminance or compared with a reference pattern or a reference non- . aggregation pattern and, further, a continuous stage dilution series of a specimen sample is formed, or the like.
The automatization of the discrimination for the aggregation patterns is accomplished by optical means and electric calculation processing means for electrically processing the aggregation patterns which are obtained by the optical means.
FIG. 9 shows a conventional example. In the conventional example shown in FIG. 9, an aggregation pattern P in a well (reactive vessel) 100A formed on a microplate 100 is optically projected onto a CCD line sensor 101. One of the line sensor 101 or microplate 100 is sequentially finely moved relative to the other in the direction perpendicular to the paper surface, thereby obtaining a (light and dark) two-dimensional image of the aggregation image P. In FIG. 9, reference numeral 102 denotes a light source, 103 indicates an image forming lens, and 104 a lens holder.
However, in the conventional example, the sensor output becomes remarkably dark at both end portions E and F of a window width L as shown in FIG. 10 due to aberrations or the like of the lens holder 104 and lens 103, and if such dark portions are extended, there occurs an inconvenience such that the extraction of the aggregation pattern in the central portion is obstructed. On the other hand, if the obtained data is collected and a solid diagram shown in FIG. 11 is formed and, after that, the aggregation pattern in the central portion is extracted by a proper threshold value, there often occurs an inconvenience such that dark portions are largely displayed as area data as shown, for instance, in FIG. 12 (solid line portions in the diagram) due to influences by light disturbance and electric noise.
It is an object of the invention to reduce the inconveniences of the foregoing conventional example and, more particularly, to provide a particle aggregation pattern discriminating apparatus in which disturbance factors can be effectively eliminated and aggregation pattern data can be effectively extracted, thereby improving the reliability of the whole apparatus.
The present invention preferably comprises a data memory circuit to sequentially store line data of an aggregation pattern which is output from a CCD line sensor at predetermined timings; threshold value specifying means for specifying a predetermined threshold value on the basis of the line data which is stored into the data memory circuit; and pattern area calculating means for extracting the aggregation pattern from the line data in the data memory circuit on the basis of the threshold value specified by the threshold value specifying means and obtaining a shape and an area of the aggregation pattern. The threshold value specifying means has a first maximum value specifying function to obtain the maximum value of each set of line data in the data memory circuit; a second maximum value specifying function to further obtain the maximum value of all of the aforementioned maximum values obtained by the first maximum value specifying function; and a threshold value specifying function to specify a threshold value of a predetermined magnitude on the basis of the maximum value obtained by the operation of the second maximum value specifying function. Due to this, it is intended to accomplish the above object.